Clothes dryers

ABSTRACT

THIS INVENTION CONSISTS OF A RELAY OPERABLE BY THE USER OF A CLOTHES DRYER TO ALTER THE NORMAL OPERATION OF THE MACHINE BY TURNING OFF THE HEAT WHILE THE MACHINE CONTINUES TO TUMBLE THE CLOTHS AND BLOW AIR THROUGH THEM TO COOL THE CLOTHES FOR WRINKLE FREE DRYING OF PERMANENT PRESS FABRICS, WHICH RELAY IS COUPLED TO THE CLOTHS DOOR OF THE MACHINE SO THAT WHEN THE DOOR IS OPENED THE ACTION OF THE USER IS CANCELLED, RESTORING THE DRYER HEATED TO THE NORMAL THERMOSTATIC CONTROL SO THAT THE NEXT USER OF THE MACHINE IS ASSURED TO RECEIVING FULL DRYING CAPACITY.

M. B. HEFTLER Dec. 7, 1971 CLOTHES DRYERS Filed May 15, 1970 REM Y DOOR6 WITCH GAS VALVE THERMOSTAT A/R FLOW HIGH L/M/T .Sw/Tcfl 5 W/TCH IN VEN TOR.

United States Patent ()1 zfice 3,624,918 Patented Dec. 7, 1971 3,624,918CLOTHES DRYERS Maurice Ben Heftler, 1119 Harvard Road, Grosse PointePark, Mich. 48230 Filed May 15, 1970, Ser. No. 37,720 Int. Cl. F26b19/00 US. Cl. 34-48 3 Claims ABSTRACT OF THE DISCLOSURE This inventionconsists of a relay operable by the user of a clothes dryer to alter thenormal operation of the machine by turning off the heat While themachine continues to tumble the clothes and blow air through them tocool the clothes for wrinkle free drying of permanent press fabrics,which relay is coupled to the clothes door of the machine so that whenthe door is opened the action of the user is cancelled, restoring thedryer heat to the normal thermostatic control so that the next user ofthe machine is assured of receiving full drying capacity.

This invention is for a control system for the tumbler type of clothesdryer that permits achieving superior results in the drying andfinishing of permanent press fabrics.

In the tumbler type of clothes dryer the Wet or damp clothes to be dryedare placed in a perforated drum which revolves slowly when the machineis in use and through which heated air is forced by a blower. The heatedair carries away the moisture in the clothes and the rotation causes theclothes to tumble and thus exposes all articles in the load to the sametreatment.

In the conventional machine the operation is controlled by a timingdevice which stops the machine at the expiration of a preset timeinterval. During operation the temperature of the heated air iscontrolled by a thermostat. If the time interval and temperature areadequate for the moisture content of the load of clothes, the clothesare dry when the time interval expires, and they are Warm. If the loadof clothes contains articles made of drip dry or permanent pressfabrics, these must be removed promptly and placed on hangers or formsto cool. If they are allowed to cool in a heap the wrinkles and foldspresent in the heap will be set by the cooling, and they will not be fitfor wear unless they are ironed.

If, on the other hand, the tumbling is continued in the machine, withcontinued air flow but without heat, the clothes will be cooled whilebeing tumbled and they will emerge without wrinkles. Two types ofmachines have recently appeared on the market that provide for this modeof operation of the dryer, one controlled by temperature and the othercontrolled by time.

In the temperature controlled cool down method the heat is shut off atthe expiration of the previously selected (in the case of coin operatedself service equipment, of the previously paid for) time interval butthe tumbling of the clothes and the passage of air continued until thetemperature of the air after it has passed through the clothes hasdropped to a preset value.

In the time controlled method, the heat is turned oif, but the tumblingof the clothes and the passage of the air continued, at a fixed timebefore the expiration of the previously selected time interval, if theuser selects that mode of operation by the appropriate positioning of aswitch or control.

In a dryer equipped with this invention the user, desiring to finish aload of permanent press fabrics already in the machine and havingascertained that the degree of dryness is adequate, merely presses abutton to turn off the heat, continuing the tumbling and air circulationfor the balance of the preselected time. When the machine is stopped, asit must be to check the condition of the clothes, or to remove them, thecontrol automatically resets to normal operation. When the machine isrestarted the button must be pushed again if further tumbling withoutheat is desired.

This is a unique solution to the problem of how to provide a cool downperiod at the end of a drying cycle. It has definite advantages over thetemperature method and over the time method because it is always underthe control of the operator or user and it resets itself to the normaldrying mode automatically. This is especially important in coin operatedself service equipment. It avoids claims for refunds since it cannotforget to turn on the heat, and it requires no foresight on the part ofthe user.

In the temperature controlled cool down method the heat is shut off atthe expiration of the previously selected time interval but the tumblingof the clothes and the passage of air continued until the temperature ofthe air passed through the clothes has dropped to a preset value. Thisis accomplished by the addition of a relay and a thermostat. It providesa cool down period beyond the end of every preselected time interval,whether needed or not. In coin operated equipment the user estimates thetime required to dry a load of clothes and inserts enough coins in theslot to buy the time she has estimated. She is often optimistic orhopeful and usually buys less time than required to dry the clothes.After starting the dryer she waits till it stops. Upon opening the doorshe finds that the clothes are cool, and too often still damp, and shewonders if the machine is heating properly. The time spent in coolingdamp clothes is wasted time, and it is provided free by the store owner,thus requiring more dryers than would otherwise be required in a givenstore. In the conventional mode of dryer operations the clothes are warmwhen the dryer stops, and that is what customers expect. If they arestill damp, the customer buys more time, but no time is wasted.

In the time controlled method, the heat is turned oif but the tumblingof the clothes and the passage of the air continued at a fixed timebefore the expiration of the previously selected time interval. The timeat which the heat is turned olf can be selected, within certain limits,by the owner, in the case of coin operated equipment, but the user hasno control over the start of the cool down period, nor how long it runs.If the cool down time is too short the clothes will still be warm at theexpiration of the purchased time. If more time is purchased, thepurchased interval will start with heat, and the cool down time will bethe same as in the previous cycle, and it may well be insuflicient. Itmay be impossible to cool down a large load with this arrangement.

In the use of dryers equipped with this invention, the cool down periodstarts when the user pushes the button, and it may continue for as longas the user wishes. If the clothes are not cooled to the userssatisfaction 'when the purchased time has expired the user may buy moretime and press the button to get tumbling without heat. The cool downtime does not start automatically. It starts only when the user pressesthe button. It requires a deliberate action to initiate it. Whenever themachine stops the control is automatically reset to normal operation.This is an important feature. The next user of the machine is assured ofnormal drying operation, with heat. There is no need to adjust a controlor to set the machine for a particular mode of operation. Whenever thedoor is opened and reclosed and the machine started, it will start witha normal drying cycle with heat, and so continue until the button ispushed or until the selected time interval runs out or the door isopened.

The mechanism by which the foregoing may be accomplished in a tumblertype of clothes dryer is shown in the schematic diagram. It consists ofa time switch 1 which passes current, for the selected interval of time,through a switch 2 that is opened when the door is opened to a motor 3that drives the air blower and the clothes drum or cylinder and to thegas valve circuit which opens the gas valve 4 to the burners when thethermostat 5 calls for heat if the air flow switch 6 is closed and ifthe safety limit switch 7 is not opened by excessive temperature and ifthe relay 8 is in its normal, or dropped out position.

The relay 8 is a conventional single pole two throw relay and it isconnected as follows. The moveable contact 9 is connected to one line ofthe source of power when the time switch 1 and the door switch 2 areclosed. The normally closed contact 10 supplies power to the gas valve 4through its associated control and safety switches, if the dryer is soequipped, when the relay is de-energized. The normally open contact 11is connected to one end 12 of the relay coil and to one side of the pushbutton 13.

The other side of the push button is connected to the moveable contact9. The other end 14 of the relay coil is connected to the other side ofthe power line. The time switch 4 and the door switch 2 may be placed soas to interrupt either side of the power. The operation in either caseis the same.

With the relay de-energized power is supplied to the gas valve circuitwhenever it is desired to operate the dryer, and the operation is thesame as in any conventional dryer not having the benefit of thisinvention. If the button is pushed a circuit will be closed from theline through the coil of the relay to the other side of the line,actuating the relay. The relay will be held in by the closing of thenormally open contact 11, paralleling the push button, and the normallyclosed contact 10 will be opened, interrupting power to the gas valvecircuit, thus shutting oiT the heat. The heat will remain off for aslong as the relay coil has power. When the power to the relay coil isinterrupted by opening the door, by the passage of time opening the timeswitch or by a failure of the power supply to the dryer the relay willbe de-energized and automatically restore the connections to the gasvalve circuit for normal operation.

The preferred method of obtaining the benefits of this invention is bythe use of an electric relay as described above. It could also beaccomplished by a single pole single throw switch that could be operatedby the user to interrupt the circuit to the gas valve and that would bemechanically reset to on condition by opening the door.

Nor need the benefits of this invention be restricted to gas heateddrivers. It is also applicable to electrically heated and to steamheated dryers. For such equipment the gas valve 4 in the precedingdescription is replaced by the contactor that controls the current tothe heaters for electric equipment or by the steam valve for steamheated dryers.

I claim the following:

1. In a machine for drying clothes having a rotating drum into which theclothes to be'dryed are deposited, access to said drum being controlledby a door, having means to blow air through the clothes and having meansto heat said air before it is blown through said clothes, a manuallyoperable device to turn oif the source of heat and means operated byopening and closing said clothes door to resore the source of heat.

2. In a clothes dryer having a drying chamber with a door through whichthe clothes to be dryed must be passed and having means to force airthrough said drying chamber and means for heating said air before itgoes to said drying chamber, manually operated means to turn off saidheat, and means to restore said heat actuated by the opening and closingof said clothes door.

3. In a clothes dryer having a thermostat to control the heating elementand a door giving access to the drying compartment, manual means to turnoff the heating element regardless of the requirements of the thermostatand means acutated by opening said door to restore the control of theheating element to the thermostat.

References Cited UNITED STATES PATENTS 3,471,938 10/1969 Elders 34-45CARROLL B. DORITY, 111., Primary Examiner

